1,n‐Hydrogen‐Atom Transfer (HAT) Reactions in Which n≠5: An Updated Inventory

Abstract

Hydrogen-atom transfer (HAT) counts amongst the most widely investigated routes to carbon-centered radicals. Intramolecular processes involving 1,5-HAT are widespread to promote regioselective radical "CH activation". The aim of this review is to draw up a comprehensive inventory of the less commonly encountered 1,n-radical translocations (n≠5) with the aim to update this topic with the most recent relevant data.

Amide-directed photoredox-catalysed C–C bond formation at unactivated sp3 C–H bonds

“…This outcome supports our hypothesis that an intramolecular 1,5-HAT process is operating. When there is potential for a competitive 1,6-HAT, 21 as in substrates 1m and 1n, the 1,5-HAT transfer is favored over 1,6-HAT resulting in products 3mc and 3nc . Although 1,5-HAT occurs in preference to 1,6-HAT, products arriving from sequential 1,5-HAT and then 1,6-HAT are observed when reactions are run to completion.…”

Photoinduced Remote Functionalization of Amides and Amines Using Electrophilic Nitrogen Radicals

“…Nevertheless, 1,6‐translocations could be efficiently achieved by providing an enthalpic bias to the system 20, 29. As demonstrated by the formation of 22 and 23 , there is a preference for 1,6‐HAT when this position is a tertiary center.…”

Photoinduced Remote Functionalization of Amides and Amines Using Electrophilic Nitrogen Radicals

“…[20,29] As demonstrated by the formation of 22 and 23, there is ap reference for 1,6-HATw hen this position is atertiary center. [20,29] As demonstrated by the formation of 22 and 23, there is ap reference for 1,6-HATw hen this position is atertiary center.…”

“…[16] We therefore turned our interest towards the use of amidyl radicals because of their high electrophilic character [17] and the strong N À Hb onds of the corresponding amides. Theh igh exothermicity characterizing these reactions means that early transition states are likely operating, [20] which makes the reaction parameters sensitive to polar effects.I ndeed, ag ood correlation between the nitrogen-radical electrophilicity indices (w + rc )a nd both DG8 8 and DG°was observed. To obtain more information on these aspects,w eh ave conducted computational studies on ar ange of model 1,5-HATp rocesses spanning amidyl, carbamoyl, N-Ts-aminyl, and iminyl radicals (Scheme 2A).…”